In recent years, a large sensor chip which is used in, for example, a so-called digital single-lens reflex camera has been required to operate at a high speed. A/D converters are provided for each column of a pixel array provided on the same chip and perform signal processing in parallel, which makes it possible to reduce the processing speed of the A/D converters to a relatively small value and thus reduce power consumption. However, in order to improve the processing speed, a sensor unit with low noise, a wide dynamic range, and a high power supply voltage, and a digital circuit which includes a micro transistor and operates at a very high speed at a low power supply voltage are configured to be incorporated into one chip. Therefore, the manufacturing process becomes complicated and the yield is reduced. In addition, when a high-speed operation is performed, the amount of heat generated from the chip, particularly, from the A/D converter increases, and an adverse effect, such as a reduction in image quality, due to an increase in temperature is likely to occur in the pixel array.
In some cases, in order to shield the transmission of heat from the A/D converter to the pixel array and improve the yield, a so-called multi-chip mounting structure is used in which the signal processing unit including the AID converter and the pixel array are formed by individual chips and are mounted on one glass chip.
A structure has become known in which a laminated wire obtained by alternately laminating a plurality of leads and insulating layers is connected to the solid-state imaging element which is used in the imaging apparatus, such as a digital still camera (for example, see Patent Document 1). The laminated wire and the solid-state imaging element are connected to each other by wire bonding.